I use physics to find the position of the objects, but then I can't save and go on
There are lots of issues in your file - this is not really a solution, but a start from which you should begin - in my opinion.
First - please watch tutorials about rigid body physics. I am assuming, that this is one of your first rigid body physics animations because you made a lot of things which an experienced user would not do.
What do i mean with that?

your objects aren't really separated (which is a situation which does not exist in reality) so some of your objects are overlapping at the start of your simulation. So what should Blender do with intersecting objects? Well...Blender does weird things with it, it is like dividing through 0 -&gt; you can't do it. And in reality things do not overlap.

your objects have much too high subdivisions which isn't necessary for such an easy object. You should try to use as less subdivisions as possible, because more subdivisions mean: more used memory, less performance, more thing to calculate for Blender.

if you do not have basic shapes you always should use mesh as collision objects, else the physics looks weird and not realistic

start using physics with ONE object and check out whether it works. Then add more. Check performance. If it slows down dramatically as in your case, you did something wrong (too much subdivisions in your case). you can decrease your subdivision by using a remesh modifier.

decrease the margin for the collisions to 0, else it won't look really realistic.

Really watch or read tutorials/books/manuals about blender and rigid body physics. Learn from others instead of trying out yourself because it will save you lots of time. Blender is - in my opinion - not intuitive, but an amazing too. Lot's of people went to the problems you now have - learn from them and save time.

if you did all this - you don't have to manually move your objects, because they will fall down physically correct and realistic. and in a reasonable speed.

you did not apply transforms